MY 91 7.3 wont shut off
 

My 91 wont shut off when u turn the key off. I have to pinch the fuel line to shut it off. Anyone have any ideas?

Don't pinch the fuel line that will just cavitate the injection pump and cause issues you need to pull the wire off the pump that controls the fuel solenoid. Have you taken the ip apart? Sometimes if the housing is installed wrong it will stay running.

I pulled the top off the pump.and the wires didnt shut the engine off when i unplugged them.

the fss inside the ip is probably bad meaning stuck on when was the ip replaced

OK so you took the FSS wires off the spade terminal........ that was the drivers side (USA) front IP wire correct.

The engine then still failed to shut down...... sounds like the FSS is fubar.

Private message!!! not possible yet.......

I have a TSB and info as to the correct removal/installation of the IP top cover so you can check the FSS physically.

If you have the top off now.....using 12v wire on the spade terminal and grounding the cover. The FSS should click when power applied/removed. You should notice the movement of the arms too.

please could someone send me that info too, my truck did the same thing a month ago, my starter switch broke in half. I've replaced the switch but my truck still wont start

NEED PART #
 

Need a part # for the FSS if anyone knows i would much appreciate it.

is yours bad? and how did you check it, plus what is a fss? 'cause my truck did the same thing and I've still not got it started a month later.:(

FSS = Fuel Shutoff Solenoid, it's an electrically-actuated valve that when applied power to opens the injection pump's inlet port and allows fuel to flow in the IP. When you shut your truck off you essentially cut power to the FSS, which causes it to snap closed and kill fuel flow into the the IP - enigine runs out of fuel and stops.

Thank you lcam, and the fss is located in the ip right? My starter switch on the column busted in half mid drive and that was what caused my truck to keep going. So hopefully the fss is not an issue on my truck yet.

Yes indeed, the FSS lives inside the IP, under the top cover. Those switches are a know problem by the way, I've seen quite a few of them halfway split on customers vehicles - and there was a TSB on those to boot, cause they like overheating and causing fires when they get loose like that.